Features of the Crystallization of Nanometre-Sized О±-Aluminium Oxide from Aluminium Hydroxide Gels with Seeding Introduced
G. R. KARAGEDOV, A. L. MYZ, O. V. KICHAY
Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Ul. Kutateladze 18, Novosibirsk 630128 (Russia)
Keywords: оксид алюминия, нанопорошок, синтез, aluminium oxide, nanopowder, synthesis
Abstract
Nanopowders of α-Al2O3 were synthesized through crystallization of aluminium hydroxide gel with nanoparticles introduced into it as seedings. Depending on the gel crystallization conditions, the powder consists either of weakly aggregated spherical particles or of polygons with irregular shapes. It was established that particle shape is determined by the composition of the gas phase during crystallization, in particular by water vapour pressure. The temperature at which the gel is completely crystallized into the α-phase depends on the content of micro-impurities in the solution from which the gel is formed. Under optimal synthesis conditions, α-Al2O3 nanopowders with particle size about 100 nm are reproducibly obtained. The powders exhibit good moldability and sintering ability to form almost pore-free ceramics at 1300 oC.
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